Sound propagating diaphragm



May 26, 1931. w. D. PACK 1,807,225

SOUND PROPAGATING DIAPHRAGH Filed March 9, 1928 2 Sheets-Sheet l May 26, 1931. w. D. PACK 1,807,225

I SOUND PROPAGATING DIAPHRAGM Filed March 9, 1928 2 Sheets-Sheet 2 Patented May 26, 193i- UNITED STATES PATENT or WEHRLI D. PACK, OF SALT LAKE CITY, UTAH, ASSIGNOR TO UTAH RADIO PRODUCTS COMPANY, INCORPORATED, A CORPORATION OF UTAH SOUND PROPAGATING DIAPHRAGM.

Application filed March 8, 1928. Serial No. 260,271.

My invention relates particularly to sound propagating diaphragms of a so-called cone loud speaker type. It is particularly adapted for use in connection with a radio receiving circuit for the propagation of sound waves in response to vibrations imparted to the diaphragm by an electromagnetic unit associated with the radio receiving circuit.

One object of the present invention is the provision of a sound propagating diaphragm which may be formed of inexpensive material such as paper or other fibrous substances.

' Another object of the invention relates to the provision of a sound propagating diaphragm of improved. acoustic property,

which will be of light weight and which will be simple and easy to manufacture, and which will have a relatively long length of'usefulness in comparison with the inexpensive material from which it may be formed.

A still further object of the invention relates to the method of forming the cone sound propagating diaphragm by which a diaphragm of improved qualities produced by a few simpleoperations performed upon inexpensive material.

With these and other objects in view, to be more fully set forth hereinafter, the inven-- tion consists in the novel construction, combination of elements and arrangement of parts which will be exemplified in the operation and construction herein described in the following specification and illustrated in the accompanying drawings.

The disclosure made the basis of exemplifying the present inventive concept suggests a practical embodiment thereof, but the invention is not to be restricted to the exact details of this disclosure, and the latter, therefore, is to be understood from an illustrative, rather than a restrictive standpoint.

The invention will first be described in connection with the drawings, wherein similar reference characters are used to designate corresponding parts throughout the several views, and more specifically defined and indicated in the appended claims.

Attention is directed to the drawings in Which:--

Fig. 1 represents the blank from which the diaphragm is to be formed;

Fig. 2 is a view of the blank after suitable cuts have been made thereon to facilitate the forming of a cone therefrom;

Fig. 3 is aside elevation of the cone formed in accordance With the present invention;

Fig. 4 is a detail sectional view of the cone thus formed;

Fig. 5 is a sectional view of a radio loud speaker unit embodying the present invention;

Fig. 6 is a view ofa modified form of the blank as illustrated in Fig. 1;

Fig. 7 is a View of the blank illustrated in Fig. 6, after cutting as disclosed in Fig. 2;

Fig. 8 is a side elevation of a cone diaphragm formed in accordance with the/modified form of the invention as illustrated in Figs. 6 and 7.

Referring more particularly to the drawings, Figure 1 illustrates a blank 10, upon which are impressed in any suitable manner as by a die circular crests and troughs l1 arranged concentrically from the center of the blank. The blank 10 may be formed of inexpensive paper or similar fibrous material. The corrugations formed by the crests and troughs 11 may be adapted to increase sound propagation area and to add rigidity and strength to the cone formed from the blank 10 in such a manner as to markedly improve the acoustic property of the diphragm thus formed. I

As illustrated in Figure 2, the next step in the formation of a sound propagating diaphragm according to my present invention resides in the cutting of the blank illustrated in Fig. l as shown in Fig. 2. The cutting includes the forming-of the periphery of the diaphragm circularly with respect to the center of the diaphragm and of a radius slightly exceeding the radius of the outer corrugation 11. The border of uncorrugated material 12 surrounding'the outer corrugation is then cut by a plurality of radially extending cuts 14. The cutting off also includes the provision of radially extending cuts 15 and 16. The angle divergent to these radial cuts determines the angularity of the cone to be formed from the blank. The cuts 15 and 16 terminate in a circular aperture 17 in the center of the blank adapted to form an attaching aperture at the apex of the cone.

The cut 16 is also provided with a portion 18 to form an overlying edge which may be readily secured to that portion of the cone adjacent the cut-15. The portions adjacent the cuts 15 and 16 may then be secured together as by gluing to form the structure as illustrated in Fig. 3, a cross-sectional View of which is indicated in Fig. 4, and forms a cone, the outer truncate-d portion of which'is provided with corrugations formed by the crests and troughs 11, which may be embossed in the blank before cutting. The uncorrugated marginal portion 12 provides a serrated adjacent flange adapted to extend at right angles from the axis of the cone.

As illustrated in Fig. 5, a cone so formed may be associated for use with an electromagnetic unit 20 and supporting frame 21, the marginal flange 12 being adapted to be retained between the retaining rims 22 held between the structure 21 and an enclosing cabinet 24. The apex of the cone is provided with an actuating clutch 25 secured through the aperture 17 whereby vibrations of the cone for the propagation of sound waves in response to the energization of the electromagnetic unit 20 will faithfully reproduce sound waves of improved acoustic quality. In the modified form of the invention, as

I illustrated in Fig. 6, includes the blank 10 upon which are embossed a plurality of excentrically arranged curved corrugations 30. The form of corrugation illustrated in this embodiment of the invention forms logarithmic determined spirals with respect to the apex of the cone. The corrugations thus formed are adapted to increase the area of the sound propagating surface to add to the strength and rigidity of the cone and to materially improve the acoustic properties thereof.

As illustrated in Fig. 7, the blank 10 is cut similarly to the cuts illustrated in Fig. 2, including the formation of the serrated uncorrugated border -12, the end walls 15 and 16, aperture 17 and the cut out'portion 18, the whole forming a cone, as illustrated in Fig. 8, which is adapted for use in a supporting structure as illustrated in Fig. 5.

In accordance with the provisions of the patent statutes, I have described my invention but I desire it understood that it is not confined to the particular form shown and described, the same being merely illustrative, and that the invention can be carried out in other ways without departing from the spirit of my invention, and therefore, I claim broadly the right to employ all equivalent instrun'ientalities coming within the scope of the appended claims, and by means of which, objects of my invention are attained vided with helically arranged and new results accomplished; as it is obvious that the particular embodiments herein shown and described are only some of many and accomplish these results.

Having now described my invention, what I claim and desire to secure by Letters Patent, is i 1. In a sound propagating diaphragm comprising a cone of fibrousmaterial proembossed .corrugations.

2. A sound propagating diaphragm comprising a cone of fibrous material provided with helically arranged embossed corrugations adjacent the mouth of the cone.

3. A sound propagating diaphragm comprising a cone of fibrous material provided with logarithmic determined embossed corrugations spaced from the apex of the cone.

4. A sound propagating diaphragm comprising a conical body having spaced helical corrugations embossed in said body adjacent the edge portion thereof, said corrugations being logarithmically curved and spirally arranged with respect to the apex of the cone.

This specification signed this 23 day of February, 1928.

WEHRLI D. PACK. 

